Of the biggest charitable gifts by individuals this year, only five surpassed $200 million, according to the Chronicle of Philanthropy. Four of those donations went to universities -- and one to a museum started by a very well-known family.

In May, the family that owns Wal-Mart pledged to give $800 million to the Crystal Bridges Museum of American Art in Arkansas, a museum started by Alice Walton, the daughter of Wal-Mart's iconic founder Sam.

"My family has laid a foundation on which this institution can continue to grow as a resource for our community, state and nation," Alice Walton said in a statement.

The museum said the gift would go toward operations, acquisitions and future capital improvements, or a "rainy day fund."

Chalk it up to the holiday spirit -- or just smart tax planning -- but online charitable donations are up 15% so far in December and are expected to rise even further in the final two days of the year.